Numerous studies have shown that 25 percent to 50 percent outpatients do not utilize their medications properly. Poor patient compliance has a substantial impact on disease prognosis, response to treatment, and economic cost to the patient and society. Very little informaion is available about compliance with ocular therapy. We have designed an eye drop medication monitor that closely resembles a standard 30 cc eye drop bottle and yet has the capacity of recording electronically the day and time of each medication administration. Patients prescribed pilocarpine eye drop therapy four times daily to one or both eyes for ocular hypertension or glaucoma will utilize an eye drop medication monitor. The rate of compliance with pilocarpine therapy (number of administrations per month, time spacing of the administrations) will be determined and related to a number of sociodemographic, patient, disease, treatment, and physician factors. Additional studies will be performed to determine the test-retest stability of compliance with pilocarpine therapy over time, the influence of the monitor on the rate of compliance, and whether patients ascertain the purpose of the eye drop medication monitor. Intercorrelations between various measures of compliance with pilocarpine therapy (eg., eye drop medication monitor, patient self-report, weight of pilocarpine solution utilized, patient diary of pilocarpine administration) will be determined. Various interventions (eg., written pamphlets, discussion with the physician, patient diary of pilocarpine administrations) to improve compliance with pilocarpine therapy will be tested. The impact of the rate of compliance with pilocarpine on the prognosis of patient with primary open-angle glaucoma (as determined by changes in the number and strength of anti-glaucoma medications, progressive visual field loss, and the need for glaucoma surgery) will be studied. Compliance with other topical (eye drop) ophthalmic medications (eg., timolol, epinephrine, antibiotics corticosteroids, cycloplegics, idoxuridine, adenine arabinoside) in selected acute and chronic ocular conditions will be determined.